Injection mold, method for manufacturing a bucket provided with a handle, and bucket manufactured with such injection mold

Abstract

 An injection mold for manufacturing a bucket (1) which is provided with a handle (2), the injection mold comprising two plastic supply channels (3,4) each connectable to a separate injection unit, the first plastic supply channel (3) terminating in a first mold cavity (5) in the form of the bucket (1), while the second plastic supply channel (4) terminates in a second mold cavity (6) in the form of the handle (2). The invention further relates to a bucket (1) with handle (2) manufactured with the aid of such an injection mold and to a method for manufacturing such bucket with the aid of the injection mold.

Description

[0001] The present invention relates to an injection mold for manufacturing a bucket which is provided with a handle.

[0002] Such a bucket is described, for instance, in European patent application EP-A-0 660 792. The bucket described therein has the advantage that the manufacture thereof is particularly simple in that only the injection molding operation needs to be carried out and the bucket needs to be taken from the mold to obtain a finished bucket with handle.

[0003] The known bucket is manufactured with the aid of an injection mold which, for each bucket, is provided with a single mold cavity which comprises both the bucket and the handle. Accordingly, the molten plastic generally flows via the bottom of the bucket to the handle to form both the handle and the bucket. It is therefore inevitable in this method of manufacturing a bucket that the handle and the bucket are connected with each other through plastic bridges.

[0004] The drawback of the known bucket is that the handle and the bucket are always made from the same plastic. Accordingly, it is not possible to provide a known bucket with a handle of a different color and/or plastic than the bucket. When such a bucket is desired by the buyer, the manufacturer of the bucket must manufacture the bucket and the handle separately and subsequently carry out an assembly operation to attach the handle to the bucket. This has as a consequence that such buckets are considerably more costly than buckets in which the plastic and the color of the bucket and the handle are the same.

[0005] The object of the invention is to provide a solution to the problems outlined above. To that end, according to the invention, an injection mold for manufacturing a bucket which is provided with a handle is provided, which injection mold comprises at least a first and a second plastic supply channel, each connectable to a separate injection unit, the first plastic supply channel terminating in a first mold cavity, in the form of the bucket, while the second plastic supply channel terminates in a second mold cavity, in the form of the handle, the first and the second mold cavities being completely separated from each other.

[0006] With such an injection mold, as a consequence of the separate plastic supply channels, two kinds of plastic and/or colors can be simultaneously supplied to the mold, one plastic being used for forming the bucket and the other plastic for forming the handle of the bucket. Thus, in a single injection molding operation, both the bucket and the handle can be manufactured.

[0007] Further assembly operations can be omitted when the injection mold, in accordance with a further elaboration of the invention, is characterized in that the first mold cavity is formed around the second mold cavity and/or vice versa, such that the handle of the bucket with handle formed with the injection mold is assembled on the bucket.

[0008] The invention further relates to a bucket manufactured utilizing an injection mold according to the invention.

[0009] Such a bucket provides the advantage that it can be taken from the injection mold in directly finished condition, without any assembly operations, and that the properties of the plastic of the bucket may be different from the properties of the plastic of the handle.

[0010] The invention further relates to a method for manufacturing a bucket according to the invention, utilizing an injection mold according to the invention, wherein a first injector and a second injector of an injection molding machine, known per se, are connected to the first and the second supply channel of the injection mold, and wherein, thereafter, in a single process operation, using the first and the second injector, the plastic for the bucket and the handle are simultaneously supplied to the first plastic supply channel and the second plastic supply channel, respectively, whereafter, after a given solidification time, the finished bucket with handle is removed from the injection mold. By the use of the above-described method, the advantages of the injection mold according to the invention are optimally utilized, and directly, without necessitating further assembly operations and/or storage of separate parts, a finished bucket is obtained whose handle can have other properties than the bucket itself.

[0011] It is noted that U.S. patent US-A-3,861,840 discloses an apparatus and a method for manufacturing a bucket with handle, in which the mold comprises a first plastic supply channel and a second plastic supply channel. However, for each bucket, the mold comprises only a single mold cavity in which both the bucket itself and the handle thereof are molded. According to the known method, first the bucket portion is filled up with plastic by injection, while the supply of plastic to the handle is blocked. Thereafter, after the plastic of the bucket has cured, the temporary blockade in the mold cavity is removed, whereafter the plastic for the handle is supplied via the second plastic supply channel. This plastic flows into undercut openings in the bucket, already cured, so that a connection between the bucket and the handle is effected, without the bucket and the handle fusing with each other. Accordingly, in the case of the known mold, the production of a bucket takes much longer, since the bucket and the handle are molded after each other. Since, according to the invention, the injection mold comprises two completely separate mold cavities, the bucket and the handle can be manufactured simultaneously, so that in the same period of time virtually twice as many buckets can be produced.

[0012] It is further noted that U.S. patent US-A-3,443,005 discloses a method and an apparatus for manufacturing a box of a rectangular shape, which box is provided with two hinge stubs and with a lid which is provided with two pivot holes, through which reach the hinge stubs. The known box is manufactured by injection molding in an injection mold, which injection mold comprises two separate plastic supply channels, one for the box and one for the lid. The lid and the box can be molded simultaneously from different kinds of plastic. All claims of the patent in question clearly set forth that the mold cavity is separated by a "partition with a restricted orifice in said cavity which divides said cavity into individual cavities for each part of said plural part article, said cavities being interconnected". Accordingly, this publication does not disclose the teaching of keeping the mold cavities completely separated from each other. Intermixing of the different kinds of plastic via the restricted orifices is therefore possible. The method claim set forth that only a substantial intermixing of the different plastic materials is prevented. Moreover, the connection of the lid with the box is not at all undetachable. The flange 18 only needs to be moved slightly outwards to bring it beyond engagement with the hinge stub 16, so that the lid becomes detached from the box. Accordingly, there is no question of an undetachable connection. Furthermore, the publication does not relate at all to an injection mold for a bucket provided with a handle. The very time lapse between the publication of US-A-3,443,005 and the present invention shows that it cannot be obvious to those skilled in the art to use the teaching of US-A-3,443,005 for the purpose of manufacturing buckets which are provided with handles formed thereon. Even if the teaching disclosed in US-A-3,443,005 were applied to buckets, it is not a bucket according to the present invention that would be obtained. Firstly, because US-A-3,443,005 does not describe completely separated mold cavities - Fig. 5 clearly shows the mutual connection 44 between the lid and the box - and, secondly, because the hinge joint formed is not an undetachable hinge joint.

[0013] Further elaborations of the invention are described in the subclaims and will be further clarified hereinafter on the basis of two exemplary embodiments, with reference to the drawings.

Fig. 1 shows a partial top plan view of a first exemplary embodiment of a bucket with handle according to the invention;

Fig. 2 shows a partial cross-sectional/side view of the bucket represented in Fig. 1;

Fig. 3 shows a left side view of the bucket represented in Fig. 1;

Fig. 4 shows a cross-sectional view taken on line IV-IV in Fig. 2;

Fig. 5 shows a cross-sectional view taken on line V-V in Fig. 2;

Fig. 6 shows a top plan view of a second exemplary embodiment of a bucket according to the invention;

Fig. 7 shows a cross-sectional view of the connection between the bucket and the handle of the exemplary embodiment represented in Fig. 6; and

Fig. 8 shows a cross-sectional view of an injection mold intended for the manufacture of the bucket represented in Figs. 1-5.

[0014] Figures 1-5 show portions of a first exemplary embodiment of a bucket 1 with handle 2. The bucket 1 has a substantially cylindrical shell wall 8 to which is connected, adjacent the upper end of the shell wall 8, a circumferential rib 9, which extends substantially perpendicularly to the shell wall 8. Connected with the end of the circumferential rib 9 remote from the shell wall 8 is a strengthening wall 7, which extends substantially parallel to, at some distance from, the substantially cylindrical shell wall 8 of the bucket 1. In the strengthening wall 7, two substantially diametrically opposite holes 10 are provided. The handle 2 is provided with two mutually facing handle projections 11, which reach through the holes 10. The mutually facing ends of the two projections 11 are provided with a thickening 12, formed thereon, whose circumferential contour is such that it cannot pass the associated hole 10. To fully clarify the connection between the handle 2 and the bucket 1, a side view and two different cross-sectional views of the connection are represented in Figs. 3-5, respectively.

[0015] Both the handle 2 and the bucket 1 are formed in a single injection mold, represented in cross section in Fig. 8. To that end, the injection mold comprises two plastic supply channels 3, 4, which are each connectable to a separate injection unit of an injection molding machine, known per se. The first plastic supply channel 3 terminates in a first mold cavity 5, in the form of the bucket 1. The second plastic supply channel 4 terminates in a second mold cavity 6, in the form of the handle. Adjacent the mold parts forming the holes 10 in the strengthening wall 7, the first mold cavity 5 is configured around the second mold cavity 6 adjacent the projections 11, such that the handle 2 after the molding process is assembled on the bucket 1.

[0016] The injection mold with which the bucket of Figs. 1-5 is manufactured corresponds substantially with the injection mold with which the bucket of Figs. 6 and 7 is manufactured, except for a difference adjacent the connection between the handle 2 and the bucket 1. In the injection mold intended for manufacturing the bucket of Figs. 6 and 7, not the handle 2 but the bucket 1 is provided with two substantially diametrically opposite bucket projections 13. The second mold cavity 6, with which the handle 2 is molded, is designed such that the handle 2, after being molded, is provided with two handle holes 14. The bucket projections 13 referred to reach through the handle holes 14. At their mutually remote ends, the bucket projections 13 are provided with a thickening 15, formed thereon, whose circumferential contour is such that it cannot pass the associated handle hole 14. In the injection mold for forming this bucket, the second mold cavity 6 adjacent the handle holes 14 will surround the first mold cavity 5 adjacent the bucket projections 13, such that after the bucket is removed from the injection mold, the handle 2 and the bucket 1 are undetachably connected with each other.

[0017] For forming a bucket according to the invention utilizing an injection mold according to the invention, a first injector and a second injector of an injection molding machine, known per se, will be connected to the first and the second supply channel 3, 4 of the injection mold. Thereafter, in a single process operation, using the first and the second injector, the plastic for the bucket 1 and the plastic for the handle 2 are substantially simultaneously supplied to the first plastic supply channel 3 and the second plastic supply channel 4, respectively. After a given solidification time, the injection mold is opened, so that the finished bucket 1 with the handle 2 formed thereon can be taken from the injection mold. Thereafter, the injection mold is closed again and a next bucket 1 with a handle 2 formed thereon can be manufactured. The great advantage of the above-described injection mold and the associated method for manufacturing a bucket with handle is that the plastic of the handle can possess other properties than the plastic of the bucket 1. As a consequence, for instance the handle 2 can have a different color than the bucket 1.

Claims

1. An injection mold for manufacturing a bucket (1) which is provided with a handle (2), the injection mold comprising at least a first and a second plastic supply channel (3, 4), each connectable to a separate injection unit, the first plastic supply channel (3) terminating in a first mold cavity (5) in the form of the bucket (1), while the second plastic supply channel (4) terminates in a second mold cavity (6) in the form of the handle (2), the first and the second mold cavity (5 and 6, respectively) being completely separate from each other.

2. An injection mold according to claim 1, characterized in that the first mold cavity (5) is shaped around the second mold cavity (6) and/or vice versa, such that the handle (2) of the bucket with handle molded with the injection mold is undetachably connected with the bucket (1).

3. An injection mold according to claim 2, characterized in that the first mold cavity (5) is designed such that the bucket (1) formed therefrom is provided with a strengthening wall (7), which extends substantially parallel to, at some distance from, the substantially cylindrical shell wall (8) of the bucket (1), and is connected with this shell wall (8) via at least one circumferential rib (9) extending substantially perpendicularly to the shell wall, while in the strengthening wall (7) two substantially diametrically opposite holes (10) are provided, the second mold cavity (6) being designed and positioned with respect to the first mold cavity (5), such that the handle (2) obtained therefrom is provided with two mutually facing handle projections (11), which reach through said holes (10), while the mutually facing free ends of the two projections (11) are provided with a thickening (12), formed thereon, whose circumferential contour is such that it cannot pass the associated hole (10).

4. An injection mold according to claim 2, characterized in that the first mold cavity (5) is designed such that the bucket (1) formed therefrom is provided with a strengthening wall (7), which extends substantially parallel to, at some distance from, the substantially cylindrical shell wall (8) of the bucket (1), and is connected with this shell wall (8) via at least one circumferential rib (9) extending substantially perpendicularly to the shell wall (8), while on the strengthening wall (7) and/or on the shell wall (8) two substantially diametrically opposite bucket projections (13) are provided, the second mold cavity (6) being designed and positioned with respect to the first mold cavity (5), such that the handle (2) obtained therefrom is provided with handle holes (14), through which reach said bucket projections (13), while the mutually remote free ends of the two bucket projections (13) are provided with a thickening (15), formed thereon, whose circumferential contour is such that it cannot pass the associated handle hole (14).

5. A bucket manufactured utilizing an injection mold according to any one of claims 1-4.

6. A bucket according to claim 5, characterized in that the plastic of the bucket (1) has other properties than the plastic of the handle (2).

7. A bucket according to claim 6, characterized in that the handle (2) has a different color than the bucket (1).

8. A method for manufacturing a bucket (1) according to any one of claims 5-7, utilizing an injection mold according to any one of claims 1-4, wherein a first injector and a second injector of an injection molding machine, known per se, are connected to the first and the second supply channel (3, 4) of the injection mold, and wherein, thereafter, in a single process operation, using the first and the second injector, the plastic for the bucket (1) and the handle (2) are simultaneously supplied to the first plastic supply channel (3) and the second plastic supply channel (4), respectively, whereafter, after a given solidification time, the finished bucket (1) with handle (2) is removed from the injection mold.

Drawing